Process for acylation or alkylation of aromatic compounds in hydrogen fluoride

Abstract

A continuous process is disclosed for the acylation or alkylation of aromatic compounds in hydrogen fluoride. The aromatic compound is sufficiently insoluble in hydrogen fluoride that a two phase reaction medium forms. However, surprisingly, the product acylated or alkylated aromatic compound is soluble in hydrogen fluoride. The present invention particularly relates to use of a continuous, multi-stage process for carrying out the acylation or alkylation reaction. In the multi-stage process, the continuous phase can be either the hydrogen-fluoride rich phase or the aromatic compound-rich phase. The movement of the continuous phase relative to the non-continuous (dispersed) phase can be countercurrent or concurrent. The multi-stage process can be operated in a manner such that the aromatic compound feed to the reaction is entirely consumed or such that unreacted aromatic compound is recycled.

We claim: 
     
       1. A continuous process for the acylation of aromatic compounds in hydrogen fluoride, said process comprising the steps of: (a) feeding liquid hydrogen fluoride and at least one acylation agent into an extractor-reactor to form a first, hydrogen-rich phase;   (b) feeding an aromatic compound-comprising material into said extractor-reactor to form a second, aromatic compound-rich phase; and   (c) contacting said first, hydrogen fluoride-rich phase with said second, aromatic compound-rich phase in a manner, within said extractor reactor, such that said acylation agent reacts with said aromatic compound to form an acylation product of said aromatic compound which is extracted into said hydrogen fluoride-rich phase wherein said acylation agent is selected from the group consisting of acetyl fluoride, a combination of acetic acid and acetyl fluoride, a combination of acetic anhydride and acetyl fluoride, and a combination of acetic acid, acetic ahyydride and acetyl fluoride, and said aromatic compound is selected from the group consisting of isobutylbenzene, methylisopropylbenzene, chlorobenzene, diphenyl, diphenylmethane, triphenylmethane, naphthalene, 2-methylnapthalene, tetralin, 1,1,3,4,4-6-hexamethyltetralin and phanthrene.   
     
     
       2. The process of claim 1, wherein at least a portion of said aromatic compound remains unreacted after step c), and wherein said unreacted aromatic compound is externally recycled, whereby said unreacted aromatic compound is used in combination with fresh aromatic compound to continue the reaction within said extractor-reactor. 
     
     
       3. The process of claim 1, wherein essentially all of said aromatic compound of said second phase is reacted after step c). 
     
     
       4. The process of claim 1, claim 2, or claim 3, wherein said aromatic compound is selected from the group consisting of isobutylbenzene; 1,1,3,4,4,6-hexamethyltetralin; and methylisopropylbenzene. 
     
     
       5. The process of claim 1, claim 2, or claim 3, wherein said hydrogen fluoride-rich phase is the continuous phase of said extractor-reactor reaction medium. 
     
     
       6. The process of claim 1, claim 2, or claim 3, wherein said aromatic compound-rich phase is the continuous phase of said extractor-reactor reaction medium.